Citi Bike and “Reactionary Biking”

We at the NYU Rudin Center got an early look at Citi Bike’s new trip data and found exciting snippets, such as where it’s clear that New Yorkers hopped off delayed subways and onto bikes, transferred from ferries, or attended events at Barclays Center. (Check out our video of 48 hours in the life of Citi Bike, now live on the NYTimes website.)

In fact, for the month of September, there is evidence of “reactionary biking,” in which subway riders encountering delays likely switched modes to bike share for that trip. The chart below demonstrates a moderate correlation between subway delays and Citi Bike usage throughout September: when delays increase, so does bike share ridership.

Reactionary biking is indicated during particular instances: for example, on September 17th at 7:45 a.m., the MTA sent an alert that the 2/3 train was delayed at Wall Street, in the heart of Citi Bike’s stations. In the half hour surrounding this alert, seventeen rides were recorded along the 2/3 route within four stops of the Wall Street Station; they were not repeated at the same time the following day. The increased rides on days heavy with delays, coupled with September’s pleasant weather (with temperatures ranging from 59 to 76 on average), lead to the conclusion that New Yorkers are avoiding or escaping transit delays by taking to bike share. As Citi Bike expands across New York City, it will provide a more comprehensive alternative to delayed transit.

Citi Bike has become an important mode in New York’s diverse transportation landscape, both as a method of active transport and an essential connection to the transit network; we are eager to analyze this data to understand its role in New York-area mobility.

Data notes:

The chart accounts for unplanned service changes only; it does not include planned weeknight and weekend service diversions (and their occasional cancelations) relating to construction work.

Dates recorded are for bike trip starts only; trips ending on subsequent days are recorded on the days on which the trips started.